Upscale is $0.20: 1K Nano Banana 2.1 plus upscale $0.30 vs 4K $0.20

Rendering a Nano Banana 2.1 image at 1K ($0.10) and then running Sume's Image Upscale ($0.20) costs $0.30, which is more than rendering it at 4K directly for $0.20. Upscaling pays off when you already have the image and cannot regenerate it, not when you are generating from a prompt.

The two routes priced

Sume's Image Upscale row is $0.20 per image, and the catalog notes it reserves about 16 megapixels of generative output. The generation rows are Sume's catalog prices as of 2026-10-09.

When upscaling still makes sense

The comparison only holds when the model can produce 4K from the prompt. Upscaling is the better route when the image is not something you can regenerate:

• A photograph, scan or customer-supplied picture that exists only at low resolution.
• A generated image you have approved and want to keep exactly as it is, since a new render at 4K from the same prompt gives a different picture.
• A model or tier that does not offer 4K, such as a 1K-only row.

The cheapest honest plan

For generated art, draft at a low tier, choose the winner, then re-render only that choice at 4K. With GPT Image 2.5, 30 low drafts at $0.02475 cost $0.7425, and rendering three winners at high 4K costs 3 x $0.2225 = $0.6675, for $1.41 total. Upscaling the same three drafts would be 3 x $0.20 = $0.60 on top of the drafts, for $1.34, but the upscaled image keeps the draft's composition and detail rather than a fresh high-quality render.

So the cost is close; the choice is about whether you want the draft's exact picture (upscale) or the model's best render of the prompt (regenerate). The Image Upscale price does not depend on the input size, per the catalog row, so a small and a large source cost the same.

Check the output

Upscale a single image and compare it with a native 4K render before you commit a batch. The catalog describes Image Upscale as generative output at about 16 megapixels, so the result is a re-synthesis of the input rather than a plain resample, and fine detail may differ from the source. Judge on your own images, since this post makes no quality claim.